Selective feeding behavior of Spissistilus festinus (Hemiptera: Membracidae) among Fabaceae and Vitaceae plants identified by choice assays

The treehopper Spissistilus festinus [Say, 1830] (Hemiptera: Membracidae) is not a direct pest of winegrapes (Vitis vinifera) but poses a threat to vineyards as a vector of grapevine red blotch virus (GRBV). While previous no-choice assays suggested a preference for Fabaceae for feeding and reproduction, recent gut content analyses revealed frequent feeding of S. festinus on Vitaceae, particularly free-living V. californica and its hybrids, within northern California vineyards. To better understand host selection and feeding behaviors of S. festinus, we conducted choice assays using excised leaves of Fabaceae (snap bean, alfalfa) and Vitaceae (winegrape, V. californica, V. californica hybrid). In two-choice assays, S. festinus more often visited snap bean, though Vitis species were also attractive when present. In four-choice contexts, snap bean remained a preferred host, followed by V. californica and winegrapes. These results confirmed the polyphagous tendencies of S. festinus and provided new insights into the feeding behaviors of this treehopper species.